Article 38 Aircraft weight scheduleI1
United Kingdom
Every aircraft for which a certificate of airworthiness or permit to fly issued under this Order is in force must be weighed, and the position of its centre of gravity determined, at such times and in such a manner as the Governor may require or approve in the case of that aircraft.
When the aircraft is weighed the operator of the aircraft must prepare a weight schedule showing—
either the basic weight or such other weight as may be approved by the Governor for that aircraft; and
either the position of the centre of gravity of the aircraft at its basic weight or such other position of the centre of gravity as may be approved by the Governor for that aircraft.
Subject to article 171, the weight schedule must be preserved by the operator of the aircraft for at least six months after the next occasion on which the aircraft is weighed for the purposes of this article.
In this article “basic weight” means the empty weight of the aircraft established in accordance with the type certification basis of the aircraft.